XQuery 1.0: An XML Query Language
W3C Working Draft 12 November 2003
A.2.2 Lexical Rules
This section should be deleted, or at least made non-normative.
I have made this point several times before:
http://lists.w3.org/Archives/Public/www-xml-query-comments/2002Jan/0002.htmlhttp://lists.w3.org/Archives/Public/public-qt-comments/2002Aug/0021.htmlhttp://lists.w3.org/Archives/Public/public-qt-comments/2002Nov/0105.htmlhttp://lists.w3.org/Archives/Public/public-qt-comments/2004Jan/0407.html
I've received a few replies, but never a satisfactory justification.
This time, I'll presumably at least get an official WG response.
Here's a summary of my objections to this section:
(1) It's error-prone.
(2) It's poorly defined.
There's only a vague description of the automaton. There's no
definition of:
--- its possible configurations;
--- how its configuration is changed by each different kind of
transition;
--- what its initial and accepting configurations are.
Moreover, there's no description of how the automaton ascertains
which pattern (of the currently legal patterns) matches the current
input. (Note that most automata don't have to deal with this,
because their "pattern" vocabulary is the same as their input
vocabulary.)
(3) It favours a particular implementation strategy, making conformance
more difficult for anyone choosing to use a different strategy.
All of which could be improved or excused if it were actually necessary,
but:
(4) It isn't necessary. It's redundant, given the rest of Appendix A.
Or, if it actually *does* express a requirement not expressed
elsewhere, then either it's a mistake, or it *should* be expressed
explicitly elsewhere. And if you don't understand the implications
of A.2.2 enough to *know* whether it expresses unique requirements,
then that lack of knowledge alone should tell you that you can't
risk making it normative.
-Michael Dyck